1. Field of the Invention
The present invention relates to a paper magazine core for rotatably supporting a roll of photosensitive material in a paper magazine for guiding and feeding a photosensitive material to a printer or other processing apparatus.
2. Description of the Related Art
A printer for printing images from negative film onto photographic paper or other such photosensitive material is loaded with a paper magazine containing a roll of photosensitive material wound on a paper tube. The photosensitive material is drawn out of the paper magazine and conveyed to the printer during printing of images on the photosensitive material. After printing, the printed photosensitive material is sent from the printer to a developer for development.
This roll-type photosensitive material is, in a darkroom or the like, first fitted on a core and then loaded into the paper magazine together with the core. The core has an inner core that is inserted into the paper tube and a pair of flange members that restrain the end faces of the photosensitive material to prevent the roll of photosensitive material from moving laterally (in the widthwise direction of the material) along the inner core. Once the inner core has been inserted into the paper tube of the photosensitive material roll and the roll has been positioned laterally by the flange members, the photosensitive material is loaded into the paper magazine. Photosensitive materials come in various widths (frequently referred to as sizes in this specification), two typical sizes being 102 mm and 254 mm. Moreover, size standards may differ between different countries. The flange members of the core are therefore made movable in the longitudinal direction of the inner core so that they can position the photosensitive material roll laterally according to its size. The structure of a conventional core is illustrated in FIG. 10. As shown in FIG. 10, an inner core 71 is formed from both ends toward the center with multiple grooves 74, 75. The grooves 74, 75 are formed at locations matched to the different sizes of photosensitive material that may be used. Each groove 74 is paired with a groove 75 and the members of each pair are laterally symmetrical with respect to the line X bisecting the inner core 71. Marks are affixed near the grooves 74, 75 so the user can quickly see how they are paired. Flange members 72, 73 are fastened at the pair of grooves 74, 75 matched to the size of the photosensitive material used.
As shown in FIG. 11, each of the flange members 72, 73 has two half-disk-shaped members 76, 77 that are separably joined into a disk-shaped member via tension springs 78 and guide members 79. The flange member 72 (73) is formed at its center with a hole portion 80 for insertion of the inner core 71. The inner surface of the hole portion 80 is formed with ridge portions 81 for engagement with the grooves 74, 75 of the inner core 71. To fasten the flange member 72 (73) to the inner core 71, the user draws the half-disk-shaped members 76, 77 apart against the force of the springs 78 to enlarge the hole portion 80 (see FIG. 11), inserts the inner core 71 into the expanded hole portion 80, brings it to the position of the desired groove 74 (75), and allows the half-disk-shaped members 76, 77 to return to their original joined condition. At this time, the ridge portions 81 of the hole portion 80 engage the desired groove 74 (75) to prevent the flange member 72 (73) from moving in the axial direction of the inner core 71. The roll of photosensitive material can therefore be positioned laterally (widthwise).
Two or more wedge-shaped portions 82 are attached at spaced locations around the center portion of the inner core 71 to extend parallel to the major axis of the inner core 71. The wedge-shaped portions 82 project radially outward from the inner core 71 somewhat beyond the portions forming the grooves 74, 75 of the inner core 71. The wedge-shaped portions 82 bite into the paper tube of the photosensitive material roll when the inner core 71 is inserted into the paper tube. This prevents the photosensitive material roll from rotating relative to the inner core 71. Another arrangement for preventing rotation of the photosensitive material roll commonly used instead of the wedge-shaped portions 82 consists of radially biased projecting members provided on the inner core 71 to thrust against the paper tube and hold it in place.
A photosensitive material roll is installed on this type of core as follows. First, the flange member 72 is engaged with the groove 74 appropriate for the size of the photosensitive material to be installed. Next, in a darkroom, the inner core 71 is inserted into the paper tube of the photosensitive material roll until the flange member 72 comes in contact with one end face of the photosensitive material roll. The hole portion 80 of flange member 73 is then expanded and fit over the inner core 71. When the flange member 73 makes contact with the other end face of the photosensitive material roll, its hole portion 80 is allowed to contract so that the flange member 73 is fixed at the position of the desired groove 75. The core with the fitted photosensitive material roll is then loaded in the paper magazine.
Thus, the forming of the inner core with grooves at spacings matched to the different photosensitive material sizes makes it possible to position the flange members at desired locations. But photosensitive materials come in many different sizes, some of which differ only very slightly, by as little as one or so millimeters. An attempt to form grooves compatible with all of the many photosensitive material sizes would therefore run into trouble because the grooves would have to be formed at such very fine spacing that they would interfere with each other. While this problem might be overcome by stocking multiple inner cores with differently spaced groove sets, this would increase the number of components required and lead to higher equipment manufacturing cost. In addition, the conventional core is structurally complicated because, as pointed out in the foregoing, the flange members have to be formed of half-disk-shaped members held together by tension springs.
Another problem is that, owing to the need to fit the photosensitive material roll on the core in a darkroom, the attachment of the remaining flange member has to be done by feel. The remaining flange member may therefore be mistakenly fastened at a groove position different from the desired one. When this happens, the positioning of the photosensitive material roll in the lateral direction cannot be effected reliably and the photosensitive material is liable to weave from side to side during feeding.
Moreover, the fact that the size of the paper tube of the photosensitive material roll also differs variously among different types of photosensitive material means that inner cores of different sizes have to be stocked in order to use photosensitive materials with different paper tube sizes. This increases the number of components required and leads to higher equipment manufacturing cost.
The present invention was accomplished in light of the foregoing circumstances. A first object of the present invention is to provide a core that can be fabricated simply at low cost.
A second object of the present invention is to provide a core that enables a roll of photosensitive material to be reliably positioned in the lateral (widthwise) direction even when the operation is conducted in a darkroom.